A 1 in 14 million chance to win the lottery, a 5% risk of cancer, a 50:50 chance of heads on a coin — we deal with probabilities all the time, but do they actually mean anything? We explore the philosophy of probability and ask whether the probabilities that come up in physics differ from those in every day life.

In the previous article we looked at a psychological study which claims to provide evidence that certain types of extra-sensory perception exist, using a statistical method called significance testing. But do the results of the study really justify this conclusion?

In March 2011 a highly respected psychology journal published a paper claiming to provide evidence
for extra-sensory perception (ESP). The claim was based largely on the
results of a very common statistical procedure called significance testing. The experiments
provide an excellent way into looking at how significance testing
works and at what's problematic about it.